The present invention relates to controlling flow in VAV systems and, more particularly, to the use of vortex valves for controlling the flow of air in variable air volume systems.
Temperature control systems in non-residential buildings typically rely upon variable air volume systems for delivering temperature controlled air to the zones or spaces within the building. Such variable air volume systems usually include an outdoor air duct for bringing outdoor air into the building, a return air duct for returning air from the spaces or zones being supplied from the variable air volume system a portion of which is to be mixed with outdoor air under control of a return air damper and the remaining return air being exhausted from the building under control of an exhaust air damper. In this typical VAV system, the mixture of return air and outdoor air is then treated through various heating coils, cooling coils, humidifiers and/or the like. A fan drives this treated air under control of a discharge air damper to a zone or zones.
The various dampers of the system are positioned by motors controlled from various controllers. The controller for the outdoor air damper, the return air damper and the exhaust air damper relies upon various inputs such as the temperature and/or humidity conditions of the return air, the temperature and/or humidity conditions of the outdoor air, and selects, based upon these inputs, an amount of outdoor air requiring the least expenditure of energy in order to treat the mixture of outdoor air and return air in order to meet the desired conditions of the zone being controlled by the variable air volume system. The discharge air damper is driven by a motor under control of a controller which can respond to temperature and/or flow sensors for maintaining the proper flow conditions for the discharge air being discharged by the fan or may operate off of a temperature sensor located within the space for delivering the right amount of temperature controlled air to satisfy the thermostat within the zone.
If the fan system supplies a plurality of zones, then a plurality of air dampers are used each regulating the supply of air to its respective zone under control of a zone thermostat for supplying the right amount of air to the respective zone for satisfying its temperature needs.
Dampers used in these types of systems or in other types of air handling systems such as fume hoods, static pressure controls for spaces or zones, and the like can require complex mechanical linkages between the dampers and the motors and are expensive to construct, install and maintain. The present invention replaces these dampers with vortex valves. Such valves have a minimum number of moving parts and are relatively simple to construct. The present invention also permits the control fluid flow path to be integrally embedded in the vortex valve enclosure at the time of manufacture for ease of construction.